1. Field of the Invention
The present invention relates to image sensors, and more particularly, to an image sensor including a color filter layer based on a photonic crystal for color separation and a method for fabricating the same.
2. Discussion of the Related Art
Generally, an image sensor is a semiconductor module that converts optical images to electrical signals. The image sensor stores and transmits image signals and displays them in a display device. The image sensor is classified into a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS) image sensor.
Both the CCD and the CMOS image sensor employ a photoelectric conversion device in an optical detecting mode. To display color for the image sensor, color filter layers are required on a photoelectric conversion device. That is, since the photoelectric conversion device does not discriminate between colors, color filter layers must be selectively formed per unit pixel to control color information. However, since color filter layers are formed of organic materials, it is difficult to form a precise pattern since process problems exist between deposited organic materials and the low resolution of a photoresist used by a dyeing method or a pigment dispersing method. Since color filtering characteristics of a pigment or dye are not ideal and exhibit low color transmittance, optical loss increases. This deteriorates output during input of external image information.
Further, complementary color filter layers or primary color filter layers separate or synthesize color information by combining three or four colors to input or output original images. However, to form three or four colors, color formation processes of three times or greater are required. Therefore, problems occur because processes are long and complicated and a great amount of subsidiary materials is required.